store a semaphore in mmap?

[ghost]

Hello,

What could be the best approach to store a binary semaphore in a struct inside a mmap file to sync the reads/write from multiple threads? Is it based on a variable?
Think database table.

All the examples initialize with new but that would not be possible here.. the semaphore has to lay locally in the allocated space

Indirectly, is the semaphore variable guaranteed to always be the same size in the future?
If it is not, then we must rethink the position of this variable inside the struct.

For example, in C++20, the binary semaphore is an int. Easy to store.

Thanks

[Darksonn]

The Tokio semaphore cannot be shared across processes. It is more complicated than the C++20 binary semaphore because it must work with async/await, requiring a totally different implementation than what is possible for blocking semaphores.

There are no guarantees about the semaphore's layout.

[ghost]

Thanks, not for me then!